Current Transformers
Types IK5, IM, IH
Current Transformers
Introduction
Trench is a recognized world leader in the
design and manufacture of high voltage
equipment for application on electric
utility and high energy industrial systems.
As part of Trench's product scope, the
Company produces a diversified range of
Instrument Transformers which are installed on 69 - 800kV electrical
systems. Instrument Transformers
include: Voltage (Potential)
Transformers (both inductive and
capacitive type), Current Transformers and Combined Instrument
Transformers (voltage and current
transformer in one unit).
Current Transformers must convert high transmission line currents
(up to 5000 A) to standardized
low and easily measurable values,
which will be used for metering,
protection and control of the high
voltage system. As such, the need
for accurate and reliable current
transformation is essential.
Fig. 1
Type IH-650,
high accuracy
current transformer
2
This brochure will detail the features and characteristics of Types
IK5, IM and IH Current Transformers. Please refer to Trench brochure
E210 for additional general information
concerning high voltage Instrument
Transformers.
Features
• meet all ANSI and IEC metering
and protection class accuracies
(other standards on request)
• rated primary currents up to
3000 A
• applications from 25 kV to
230 kV
• Trench Management System has
been certified to ISO 9001, ISO
14001 and OHSAS 18001
• Hi-ACC ™,0.15% accuracy units
available
• highly refined and processed
oil/paper insulation system
• head type design of low weight
and minimum oil volume
• excellent seismic performance as
a consequence of optimized
design of flanges, porcelain and
their interconnection
• excellent control of internal and
external insulation stresses
• hermetically sealed construction
using nitrile rubber gaskets
• uniformly distributed secondary
windings guarantee accurate
transformation at both rated and
high currents
• essentially unaffected by stray
external magnetic fields
• stable accuracy over a long
period of time
Fig. 2
Sectioned
view of a
typical IK5
current
Transformer
• corrosion resistant aluminum
head polyester powder coated
3
Construction
Standard Equipment
Trench type IK5, IM and IH Current
Transformers are defined as "head
type" Current Transformers. These
CT's are designed and constructed
with the well proven, highly
reliable, oil/paper insulation system.
Each porcelain housed, hermetically
sealed Current Transformer is
equipped with an aluminum head
housing which also serves as the
expansion chamber, compensating
for oil volume changes by means
of a dry nitrogen cushion above
the oil. All Current Transformers
feature a single core with dual
ratio, tapped secondary winding.
• aluminum flat pad primary
terminal and ground terminal
The Current Transformer type designations are defined as follows:
• IK5- 0.3% accuracy, BO.1-1.8,
standard short time current
rating
• IM - 0.3% accuracy, BO.1-1.8,
up to 5 times higher short time
current rating on selected
models
• IH - 0.15% accuracy, BO.1-1.8,
standard short time current
rating
For ratio arrangements, individual
customer requirements may
specify:
• single ratio
• dual ratio by secondary tap
(suffix S)
• dual ratio by series-parallel of
primary (suffix P)
• multi-ratio by secondary tap
(suffix M)
4
• lifting holes on base
• magnetic oil level gauge
• oil filling plug with nitrogen
filling valve
• oil drain valve
• secondary terminal box with
3-1.5" (38mm) knockouts
• primary bypass protector
• slide link to visibly short full
winding
Catalog Numbering
System
Current Transformer Selection
Series
IK5
Design with active elements in the dome, porcelain insulator,
0.3% accuracy class,with short-time mechanical and thermal
ratings as listed on page 4.
IM
Same design as IK5 with increased mechanical and shorttime thermal current ratings.
IH
Denotes Hi-ACC TM High Accuracy 0.15% metering type.
Other features same as IK5 design.
BIL (kV) Basic Lightning Impulse Insulation Level.
Primary Amperes
Indicates highest nominal primary amperage.
(Suffix No 1)
For example:
50 A
= 500
200 A = 201
2000 A = 202
Ratio Arrangements
SDual ratio by secondary tap
(Suffix No 2)
BlankSingle ratio
PDual ratio by series-parallel
of primary
MMulti-ratio by secondary tap
Catalog numbers are composed
of two parts as shown in the
example on the right.
• The TYPE contains the transformer SERIES designation and
the BIL (kV) rating. In this example, IK5-650.
• The SUFFIX is listed in two parts
PRIMARY AMPERES and RATIO
ARRANGEMENTS. In this
example, 202S.
IK5-650-202 S
Current Transformer Selection
Series
IK5
IM
IH
BIL Catalog Number
(kV)Type + Suffix (No.1+ No.2)
150
200
250
350
550
650
750
900
1050
IK5-150IK5-200IK5-250IK5-350IK5-550IK5-650IK5-750IK5-900IK5-1050-
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
350
550
650
750
900
1050
IM-350IM-550IM-650IM-750IM-900IM-1050-
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
150
200
250
350
550
650
750
900
1050
IH-150IH-200IH-250IH-350IH-550IH-650IH-750IH-900IH-1050-
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.1)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
(No.2)
Notes: Other ratios available, please consult factory.
For multiple secondary windings. please consult factory.
Primary
Nominal Suffix
Amperes No. 1
50
100
150
200
300
400
600
800
1000
1200
1500
1600
2000
3000
50
100
150
200
300
400
600
100
150
200
300
400
600
800
1000
1200
1500
1600
2000
3000
500
101
151
201
301
401
601
801
102
122
152
162
202
302
500
101
151
201
301
401
601
101
151
201
301
401
601
801
102
122
152
162
202
302
Ratio Arrangements (Suffix No.2)
S
Blank
M
P
(Dual Ratio) (Single Ratio) (Multi Ratio) (Dual Ratio)
25/50:5
50/100:5
75/150:5
100/200:5
150/300:5
200/400:5
300/600:5
400/800:5
500/1000:5
600/1200:5
750/1500:5
800/1600:5
1000/2000:5
1500/3000:5
25/50:5
50/100:5
75/150:5
100/200:5
150/300:5
200/400:5
300/600:5
50/100:5
75/150:5
100/200:5
150/300:5
200/400:5
300/600:5
400/800:5
500/1000:5
600/1200:5
750/1500:5
800/1600:5
1000/2000:5
1500/3000:5
50:5
100:5
150:5
200:5
300:5
400:5
600:5 600:5MR
800:5
1000:5
1200:5 1200:5MR
1500:5
1600:5
2000:5 2000:5MR
3000:5 3000:5MR
50:5
100:5
150:5
200:5
300:5
400:5
600:5 600:5MR
100:5
150:5
200:5
300:5
400:5
600:5
800:5
1000:5
1200:5
1500:5
1600:5
2000:5
3000:5
-
Consult
Factory
Consult
Factory
50X100:5
75X150:5
100X200:5
150X300:5
200X400:5
300X600:5
400X800:5
500X1000:5
600X1200:5
750X1500:5
800X1600:5
1000X2000:5
1500X3000:5
5
Accuracy Selection
Series
IK5
IM
IH1)
Metering Accuracy
% of Nameplate Rating
Optional
100%
10%
5%
1%
Not
Not
0.3%
0.6% specified
specified
0.3%
0.6%
by ANSI
by ANSI
0.15% 2) 0.15% 2) 0.15%2)
0.3%4)
Burden
Rating Class
Relay Accuracy
Relay
Class
BO.1-1.8
C200 3
BO.1-1.8
BO.1-1.8
–
–
1 For additional information on HI-ACC TM transformers consult factory.
2 The 0.15% parallelogram is constructed using the same principles as the 0.3% parallelogram in
accordance with ANSI Standard C57.13, exept the maximum phase angle and ratio correction
factors of the 0.15% parallelogram are half those of the 0.3% parallelogram.
3 Rating is based on highest ratio. Higher relay ratings are available.
4 Available on some ratios listed below (consult factory for details)
Electrical Characteristics
Series
BIL
Applied Creepage
(kV) Withstand Distance
(kV)
IK5
IM
IH
in/mm
Strike
Distance
in/mm
150
200
250
350
550
650
750
900
1050
50
70
95
140
230
275
325
395
460
34/864
34/864
52/1321
52/1321
92/2337
112/2845
169/4293
169/4293
214/5436
13/330
13/330
24/610
24/610
40/1016
48/1219
65/1651
65/1651
84/2134
350
550
650
750
900
1050
140
230
275
325
395
460
52/1321
101/2565
131/3327
169/4293
169/4293
214/5436
24/610
42/1067
54/1372
65/1651
65/1651
84/2134
150
200
250
350
550
650
750
900
1050
50
70
95
140
230
275
325
395
460
34/864
34/864
52/1321
52/1321
101/2565
131/3327
169/4293
169/4293
214/5436
13/330
13/330
24/610
24/610
42/1067
54/1372
65/1651
65/1651
84/2134
For units rated C400 or C800 relay class rating consult factory
Note: Consult factory for ratios not listed.
6
Ratio
25/50:5
50/100:5
75/150:5
100/200:5
150/3005
200/400:5
300/600:5
400/800:5
500/1000:5
600/1200:5
750/1500:5
800/1600:5
1000/2000:5
1500/3000:5
25/50:5
50/100:5
75/150:5
100/200:5
150/300:5
200/400:5
300/600:5
100:5
150:5
200:5
300:5
400:5
600:5
800:5
1000:5
1200:5
1500:5
1600:5
2000:5
3000:5
Thermal
Rating
Factor
at 30° C
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.5
2.0/1.0
2.0/2.0
2.0/2.0
2.0/2.0
2.0/2.0
2.0/2.0
2.0/2.0
2.0/2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
1.875
1.5
1.0
Mechanical
Short-Time
Current
Thermal Current
Rating
Rating
kA RMS Max. (1 sec.) kA RMS
4
8
12
15
24
30
60
60
60
120
120
120
120
120
21
31
49
63
63
63
63
8
12
15
24
30
30
60
60
60
120
120
120
120
3
6
10
13
20
26
39
52
60
90
90
90
90
90
21
31
49
63
63
63
63
6
10
10
20
25
25
50
50
50
90
90
90
90
Dimensional Table
Type
Series BIL (kV)
IK5-150
150
A
50.26
(1277)
IK5-200 200 50.26
(1277)
IK5-250 250 61.13
(1553)
IK5-350 350 61.13
(1553)
IK5-550 550 80.38
(2042)
IK5-650 650 88.45
(2247)
IK5-750 750 120.13
(3051)
IK5-900 900 120.13
(3051)
IK5-1050 1050 138.50
(3518)
B
C
D
39.19
(995)
39.19
(995)
50.06
(1272)
50.06
(1272)
69.12
(1755)
77.19
(1961)
100.62
(2556)
100.62
(2556)
119.00
(3023)
13.40
(340)
13.40
(340)
24.21
(615)
24.21
(615)
40.27
(1023)
48.34
(1228)
65.28
(1658)
65.28
(1658)
83.65
(2125)
10.50
(267)
10.50
(267)
10.50
(267)
10.50
(267)
11.00
(279)
11.00
(279)
14.00
(356)
14.00
(356)
14.00
(356)
Dimensions (in./mm) 1
E
F
G
14.00
(356)
14.00
(356)
14.00
(356)
14.00
(356)
14.00
(356)
14.00
(356)
21.00
(533)
21.00
(533)
21.00
(533)
13.94
(354)
13.94
(354)
13.94
(354)
13.94
(354)
13.94
(354)
13.94
(354)
20.58
(523)
20.58
(523)
20.97
(533)
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
24.00
(610)
24.00
(610)
24.00
(610)
Creepage Weight Oil
H
I
J
K
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
17.00
(432)
24.00
(610)
24.00
(610)
24.00
(610)
23.75
(603)
23.75
(603)
23.75
(603)
23.75
(603)
28.00
(711)
28.00
(711)
31.75
(806)
31.75
(806)
31.75
(806)
17.25
(438)
17.25
(438)
17.25
(438)
17.25
(438)
22.25
(565)
22.25
(565)
25.25
(565)
25.25
(565)
25.25
(565)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
4.50
(114)
in(mm)1 lb(kg)1 gal(l)
34
(864)
34
(864)
52
(1321)
52
(1321)
92
(2337)
112.
(2885)
169
(4293)
169
(4293)
214
(5436)
295
(134)
295
(134)
335
(152)
335
(152)
600
(272)
640
(291)
1640
(745)
1640
(745)
1800
(817)
11
(42)
11
(42)
14
(53)
14
(53)
29
(110)
30
(114)
79
(299)
79
(299)
87
(329)
1 Weights and dimensions are approximations only and are not intended for construction purposes.
Note: Dimensions for Series IH and IM differ from that listed for the IK5. Please contact factory for specific details.
7
Trench Facilities
The Trench Group is your
partner of choice for electrical
power transmission and
distribution solutions today;
and for the development of
your new technology solutions
of tomorrow.
Trench® Austria GmbH
Paschinger Strasse 49
Postfach 13
A-4060 Linz-Leonding
Austria
Phone: 43-732-6793-0
Fax: 43-732-671341
Trench® Limited
Instrument Transformer Division
390 Midwest Road
Scarborough, Ontario
Canada M1P 3B5
Phone: 416-751-8570
Fax: 416-751-6952
Trench® Brasil Ltda
Via Expressa de Contagem, 2685
Contagem, Minas Gerais
CEP 32370-485
Brazil
Phone: 55-31-3391-5959
Fax: 55-31-3391-1828
Trench® Limited
Power Line Carrier Division
815 Middlefield Road, Unit 6A
Scarborough, Ontario
Canada M1V 2P9
Phone: 416-291-8544
Fax: 416-291-5581
Trench® China
MWB (Shanghai) Co., Ltd.
No. 3658, Jiancheng Road
Minhang, Shanghai
Peoples Republic of China
200245
Phone: 86-21-54720088
Fax: 86-21-54723118
Trench® France S.A.
16, Rue du Général Cassagnou
B.P. 70 F-68 302
St. Louis, Cedex
France
Phone: 33-3 89-70-2323
Fax: 33-3 89-67-2663
Trench® High Voltage
Products Ltd., Shenyang
No. 2 Zhengliang Er. Road
Jing Shen Xi San Street
Dao Yi Economic Development Zone
Shenyang 110136 P.R. China
Phone: 86-24-89722688
Fax: 86-24-89737200
Trench® Limited
Bushing Division
432 Monarch Avenue
Ajax, Ontario
Canada L1S 2G7
Phone: 905-426-2665
Fax: 905-426-2671
Trench® Limited
Coil Product Division
71 Maybrook Drive
Scarborough, Ontario
Canada M1V 4B6
Phone: 416-298-8108
Fax: 416-298-2209
Trench® Germany GmbH
Nürnberger Strasse 199
D-96050 Bamberg
Germany
Phone: 49-951-1803-0
Fax: 49-951-1803-224
Trench® Switzerland AG
Lehenmattstrasse 353
CH-4028
Basel
Switzerland
Phone: 41-61-315-51-11
Fax: 41-61-315-59-00
Trench® (UK) Limited
South Drive
Hebburn
Tyne & Wear
NE 31 1 UW
Phone: 44-191-483-4711
Fax: 44-191-430-0633
www.trenchgroup.com
E 217.31
Subject to change without notice (05.2006)
Printed in Canada.